Plug-style air-conditioning service valve

ABSTRACT

In a plug-style valve, such as an air-conditioning service plug-style valve, basically including a valve body, a stem, a retainer including a service fitting and a valve core, and a cap, the plug including an intermediate O-ring, between the valve body and the plug, disposed in an intermediate O-ring seal groove of a serpentine shape and having integral first and second O-ring groove portions, the intermediate O-ring being stretched a predetermined amount during installation and defining, therebetween and the valve body and the plug, a closed volume without a primary lateral passage in the plug, with the O-ring stretching preferably being in excess of about 15% to offset refrigerant medium absorption effects that will cause the O-ring to swell, become too large and become loose within its retaining groove, with the single cap including a redundant seal that covers both the valve actuation stem and the service fitting

CROSS-REFERENCE TO RELATED CASES

The present application claims the benefit of the filing date of U.S.Provisional Application Ser. No. 60/523,508, filed Nov. 19, 2003, thedisclosure of which is fully incorporated herein by reference.

FIELD OF THE INVENTION

The present invention pertains to a plug-style valve, e.g., for use asair-conditioning service valves that previously traditionally used frontseat valve designs. More particularly, the invention utilizes, amongother things, a novel plug that includes an intermediate O-ring disposedin an intermediate O-ring seal groove of a serpentine shape havingintegral first and second O-ring groove portions, with this O-ring beingstretched, at installation, preferably being in excess of about 15% tooffset refrigeration medium absorption effects thereon.

BACKGROUND OF THE INVENTION

A condensing unit is a key component of a typical residential splitair-conditioning and heat pump system, wherein the condensing unit isprimarily comprised of the compressor, the outdoor coil, fan andconnections. During the installation of such a system, the outdoor unitis connected to two lines (high and low side) that convey refrigerantmedium to and from the indoor coil and expansion device. These twoconnections, on the condensing unit, are made at the liquid (high side)and the suction (low side) service valves. Since the suction sideservice valve conveys gaseous refrigerant medium, it is a substantiallylarger valve than the liquid side service valve that conveys the liquidrefrigerant medium. After the necessary braze connection is made, theselines, between the indoor and outdoor coils, are evacuated of airthrough charge ports located on the service valves. Thereafter, theshut-off valves are opened thus allowing pre-charged refrigerant mediumto flow from the condensing unit throughout the noted system.

The main functions of a typical state of the air-conditioning servicevalve are to:

-   -   1. Retain pre-charged refrigerant medium in the condensing unit        before installation;    -   2. Provide a shut-off for the possibility of a “pump-down”.        During the “pump-down” process, the liquid service valve is        closed and the compressor is turned on so that the refrigerant        medium is conveyed to and stored in the condensing unit. Once        this process is completed, the suction line service valve is        closed. In this way the indoor coil, expansion device, and        connecting lines can be accessed without removing the        refrigerant medium from the system; and    -   3. Provide a service port via which a hose connection can be        used to evacuate the refrigerant medium or monitor the system        pressure for diagnostic purposes.

A typical state of the art air-conditioning service valve exhibits agenerally “Z” flow path inherent in a front seat valve design which,however, is not conducive to a low pressure drop. While a pressure drop,in the liquid line of the system, is not usually detrimental to systemperformance, a suction line pressure drop causes a definite decrease insystem efficiency. Therefore, the suction side service valve design hasdeveloped a design stratification whereby the flow path and subsequentpressure drop associated with this valve have become important features.Some condensing unit manufacturers utilize a ball-style valve thatexhibits a large straight flow path, but the cost of this valve issubstantially higher than that of the usual front seat valve. Notsurprisingly, many manufacturers prefer the lower cost of the usualfront seat valve for the suction service valve application and willcompensate for the added pressure drop, and its associated efficiencylosses, via design changes in other areas of the system. Another benefitof the ball-style valve is the ease of actuation of the valve stem inthat turning the ball valve stem but one quarter turn will cause thevalve to open or close, while the front seat style valve requiresmultiple complete rotations of its valve stem to either open or closethe valve.

The construction of the present invention employs a valve style that ispresently not used in residential air-conditioning and heat pumpapplications, namely a plug-style valve. The use of a plug valve isadvantageous in the suction side service valve application since theflow path thereof is straight through the valve body, a keycharacteristic in pressure drop considerations. In addition, thethrough-hole in the stem of the plug valve can readily be sized forreduced pressure drop, and a plug-style valve requires only a minimalactuation motion, similar to that of a ball valve.

One of the challenges encountered in the state of the art plug valves,such as the one set forth in U.S. Pat. No. 5,234,193, to Neal Jr., alsoassigned to the assignee of the present invention, is the difficulty inretaining the circular seal on the side of the valve's stem. The notedpatent structure uses a press-in-place custom seal that can be difficultto assemble. Other plug-type valves, such as the one shown in U.S. Pat.No. 4,262,880, to Danko, et al., rely on an O-ring that is held in theside of the stem by the dovetail nature of its receiving gland, whereasthe present invention uses a serpentine gland that permits the O-ring tobe stretched substantially around the valve's stem as an improved meansto retain the seal or O-ring in its groove or gland.

The previously-noted prior art plug valves use a seal on the side of thevalve stem to seal off the valves' through holes when the valves areclosed. When the valves are opened, this seal is not utilized, and asecond O-ring around the top of the valve becomes the primary sealagainst leakage between the stem and the valve body. The unique shape ofthe present invention serpentine gland allows the O-ring located thereinto be so positioned that it functions as the primary seal againststem/body leakage when the valve is in the open position. In the presentinvention, the other O-ring around the top of the stem is the primaryseal only when the valve is closed and a secondary seal when the valveis open. This is of particular importance since an air-conditioningservice valve requires that the valve be in its open position almostexclusively after the system has been installed. In addition, the thusdouble O-ring seal, in the open position, allows for the use of a softseal, not the customary metal-to-metal seal.

A further difficulty faced by the state of the art plug valves is thepossibility of the seal being damaged by the edge formed by the insidediameter of the valve body and the valve's lateral through holes sincethe seal does contact this edge during the actuation of the valve stem.Furthermore, the seal can also contact the noted edges during theinitial assembly of the valve if, at that time, the seal is notpositioned away from the valve's through holes. In the structure of thepresent invention, the location of the serpentine gland portion thatextends around the top of the valve stem allows for the serpentineO-ring to be located away from these edges during the assembly step.

The patent literature includes a plurality of plug-type valveconstructions including: U.S. Pat. No. 3,186,437 to Buono that includesa pointer that indicates the position of a valve passage within thevalve body; U.S. Pat. No. 3,783,890 to Wurzburger, U.S. Pat. No.3,802,457 also to Wurzburger, U.S. Pat. No. 5,219,149 to Combeau, andU.S. Pat. No. 5,372,158 to Berfield, all of which pertain to plug-typevalves that employ varying styles of serpentine seals; while U.S. Pat.No. 6,216,473 B1 pertains to an air-conditioning service valve structurethat is similar to that of the present invention only in that it alsoutilizes a service port. In this structure, specifically as shown inFIG. 7, fluid flows to a recovery circuit via fluid recovery inlet port1105A, but fluid can still flow, albeit via leakage, from inlet 1102A tooutlet 1102B, since peripheral seals 1110 only prevent horizontal orlateral leakage when inlet 1102A is aligned with outlet 1102B as shownin FIG. 8, but not peripheral leakage in the FIG. 7 position. However,none of these prior art constructions teach or suggest the unique valvestructure of the present invention.

SUMMARY OF THE INVENTION

Accordingly, in order to overcome the deficiencies of the prior artdevices, the innovative plug-style valve of the present inventionprovides specific advantages over the plug-style valves used in otherindustries as well as the state of the art air-conditioning servicevalves. Advantages over traditional air-conditioning service valvesinclude:

-   -   1. The plug-style valves of the present invention provide a        lower pressure drop through the valve, similar to that of ball        valves but at a lower cost;    -   2. The plug-style valve of the present invention provides for a        minimal actuation motion, namely one quarter turn, like ball        valves but at a lower cost, as opposed to the required multiple        full rotations of the front-seat valve;    -   3. One of the difficulties a condensing unit manufacturer faces        when mounting the state of the art service valve is locating        same such that the actuation stem and service fitting thereof        are easily accessible to a service technician. This can be        challenging considering that there are two valves (gas and        liquid), each having an actuation stem and a service fitting on        adjacent sides of the valve. The plug valve of the present        invention locates the service fitting integrally within the        valve's actuation stem, thus easing mounting configuration        considerations for the condensing unit manufacturer while also        providing easier access for the service technician;    -   4. By locating the service fitting integrally within the valve's        actuating stem, it allows the number of sealing caps on the        valve to be reduced. Only one cap can now provide a redundant        seal and protect both the actuation stem and the service        fitting; and    -   5. The use of multiple seals, such as O-rings, allows for the        elimination of metal-to-metal seals on the actuation stem and        the valve cap. This permits simpler (lower strength requirement)        and lower cost valve mounting options.        Specifically, in terms of structure, in this invention an air        conditioning service plug-type valve, comprises in        combination: a. a valve body having a chamber and an inlet        opening and an outlet opening communicating with the chamber,        the valve body including, at an open end of the chamber, an        exteriorly threaded portion and a generally cylindrical pocket        portion having a deformable collar; b. a stem, including a        generally cylindrical plug with a peripheral surface, located on        one end and a contiguous actuating portion extending from        another end thereof, the plug being disposed within the chamber        and being rotatable within the chamber, about an axis between a        closed position and an open position; c. the plug including a        first, through, lateral passageway communicating with the inlet        and outlet openings when the plug is in the open position,        thereby providing a first flowpath for the fluid through the        valve, the inlet and outlet openings, together with the first        lateral passageway, being disposed along a straight axis when        the plug is in the open position; d. the plug further including        a second lateral passageway normal to, emanating from and        communicating the first lateral passageway with the valve body        chamber; e. a first seal, disposed between the valve body and        the plug in a first seal groove in the plug peripheral        surface; f. a second seal, disposed between the valve body and        the plug in a second seal groove, of a serpentine shape and        including contiguous first and second seal groove portions, in        the plug peripheral surface, the second seal being stretched a        predetermined amount during its installation into the second        seal groove and being spaced apart from the first seal and        defining, therebetween and the valve body and the plug, a closed        volume without the first lateral passageway; g. the second seal,        upon installation thereof in the second seal groove assumes the        shape of the second seal groove, thus including first and second        contiguous seal portions, the first seal portion being disposed        above the inlet and outlet openings, the second seal portion        extending from one end of the first contiguous seal portion        downwardly to below the inlet and outlet openings and then back        upwardly to another contiguous end of the first seal portion        such that one of the inlet and outlet openings is disposed        within the closed volume and the other of the inlet and outlet        openings is disposed outside of the closed volume when the plug        is in the closed position; h. the stem contiguous actuating        portion including a generally cylindrical portion, including a        radially extending stop member, adjoining the plug, a        tool-receiving portion adjoining the generally cylindrical stem        portion, and a service fitting adjoining the tool-receiving        portion, the stem further including a central axial passageway        normal to, emanating from and communicating the first lateral        passageway with the service fitting, the service fitting being        adapted for receiving a valve core for refrigerant medium        charging purposes; i. a generally annular retainer member        positioned around the stem cylindrical portion, axially within        the valve body pocket portion, with the inside diameter of the        retainer member being smaller than the diameter of the plug and        having a recessed portion of a predetermined circumferential        extent, with the stop member being received within the recessed        portion, the valve body deformable collar being adapted to be        radially inwardly swaged over the retainer member during the        assembly of the valve; j. a cap for sealing the valve cavity and        protecting the stem actuating portion, the cap including an        interiorly threaded base portion, adapted to mate with the        threaded valve body portion, and an integral truncated closure        portion having an internal cavity for covering the service        fitting and valve core; and k. a third seal, located in an        internal gland portion of the cap, adapted for sealing the cap        against the valve body swaged collar portion, upon assembly of        the cap onto the valve body.

In one version of this air conditioning service plug-type valve, thesecond lateral passageway is angularly spaced about 90 degrees from thefirst lateral passageway.

In another version of the air conditioning service plug-type valve, thesecond seal groove includes a second seal first groove portion beingsubstantially parallel with the first seal first groove, for retainingthe second seal first portion, and a contiguous second seal secondgroove portion, the second groove portion being generally U-shaped inits angular extent, for supporting the second seal second portion.

In further versions of the air conditioning service plug-type valves,the second seal first groove portion is substantially semicircular inangular extent, and the second seal second groove portion issubstantially semicircular in angular extent, or each of the second sealfirst and second groove portions are substantially semicircular inangular extent.

In yet other versions of the air conditioning service plug-type valves,the amount of stretching of the second seal is in excess of about 15%.

The present invention also pertains to a stem in an air conditioningservice plug-type valve, wherein the stem, comprises: a. generallycylindrical plug with a peripheral surface, located on one end thereofand a contiguous actuating portion extending from another end thereof,the plug being disposed in valve body having a chamber and inlet andoutlet openings communicating with the chamber, the plug being rotatablewithin the chamber about an axis between a closed position and an openposition; b. the plug including a first, lateral through passagewaycommunicating with the inlet and outlet openings when the plug is in theopen position, thereby providing a first fluid path through the valve,the inlet and outlet openings, together with the first passageway, beingdisposed along a straight axis when the plug is in the open position; c.the plug further including a second lateral passageway normal to,emanating from and communicating the first lateral passageway with thevalve body chamber; d. a first seal groove in the plug peripheralsurface for retaining a first seal therein; e. a second seal groove inthe plug peripheral surface, of a serpentine shape, for retaining asecond seal therein, the second seal being stretched a predeterminedamount during its installation into the second seal groove and beingspaced apart from the first seal groove and defining, therebetween andthe valve body and the plug, a closed volume without the first lateralpassageway; and f. the contiguous actuating portion including agenerally cylindrical portion including a radially extending stopmember, adjoining the plug, a tool-receiving portion adjoining thegenerally cylindrical portion, and a service fitting adjoining thetool-receiving portion, the stem further including a central axialpassageway normal to, emanating from and communicating the first lateralpassageway with the service fitting, the service fitting being adaptedfor receiving a valve core for refrigerant medium charging purposes.

In another version in the stem of this invention, the second seal grooveincludes a second seal first groove portion, substantially parallel withthe first seal groove, for retaining the second seal first portion, anda contiguous second seal second groove portion, substantially U-shaped,for retaining the second seal second portion.

In a further version, in the stem of this invention, at least one of thesecond seal first and second groove portions is substantiallysemicircular in angular extent.

In still an additional version of the stem of this invention, the amountof stretching of the second seal is in excess of about 15%.

In a differing version of the stem of this invention, the second lateralpassageway is angularly spaced about 90 degrees from the first lateralpassageway.

This invention also pertains to plug-style valves used in applicationsother than in air-conditioning systems, namely a plug-type valvecomprising in combination: a. a valve body having a central chamber andangularly spaced inlet and outlet openings communicating with thechamber, the valve body including, at an open end of the chamber, athreaded portion and a generally cylindrical pocket portion having adeformable collar; b. a stem, including a cylindrical plug with aperipheral surface, located at end and an integral actuating portionextending from another end thereof, the plug being disposed within thechamber and being rotatable about an axis between closed and openpositions; c. the plug including a primary lateral through passagecommunicating with the inlet and outlet openings when the plug is in theopen position, thereby providing a first flowpath through the valve, theinlet and outlet openings, together with the primary passage, beingcoaxial when the plug is in the open position; d. the plug furtherincluding an auxiliary lateral passage normal to, emanating from andcommunicating the primary passage with the valve body chamber, theauxiliary passage being angularly disposed about 90 degrees from theprimary lateral passage; e. an end O-ring, disposed between the valvebody and the plug in an end seal groove in the plug peripheral surface;f. an intermediate O-ring, disposed in the plug peripheral surfacebetween the valve body and the plug in an intermediate O-ring groove ofa serpentine shape and having integral first and second O-ring portions,the intermediate O-ring being stretched a predetermined amount duringits installation into the intermediate O-ring groove and defining,therebetween and the valve body and the plug, a closed volume withoutthe primary passage; g. the intermediate O-ring, upon the installation,assuming the serpentine shape of the intermediate O-ring groove, thusincluding first and second integral O-ring portions, the first O-ringportion being disposed on one side of the inlet and outlet openings, thesecond O-ring portion extending therefrom to another side of the inletand outlet openings and then back to another end of the first O-ringportion such that one of the inlet and outlet openings is disposedwithin the closed volume and the other of the inlet and outlet openingsis disposed outside of the closed volume when the plug is in the closedposition; h. the stem actuating portion including a cylindrical stemportion, having a stop member, adjoining the plug, a tool-receivingportion adjoining the stem portion, and a service fitting adjoining thetool receiving portion, the stem further including a central axialpassage normal to, emanating from and communicating the primary lateralpassage with the service fitting, the latter including a valve core forgaseous medium charging purposes; i. an annular retainer memberpositioned around the cylindrical stem portion, axially within the valvebody pocket portion, with the inside diameter of the retainer memberbeing of a diameter smaller than that of the plug and including arecessed portion, with the stop member being received therein, the valvebody deformable collar being inwardly deformed over the retainer member;j. a cap, for sealing the valve cavity and the stem actuating portion,having a threaded base portion, for mating with the valve body threadedportion, and an integral closure portion having an internal cavity forcovering the service fitting; and k. a cap seal, located within the cap,for sealing the valve body deformed collar portion.

In a version of the previous embodiment, the intermediate O-ring grooveincludes a first groove portion, substantially parallel with the endO-ring groove, for retaining the intermediate O-ring first portion, andan integral intermediate O-ring second groove portion, of generalU-shape in its angular extent, for retaining the intermediate O-ringsecond portion.

In a further version of the previous embodiment, the angular extent ofat least one of the intermediate O-ring first and second portions isabout 180 degrees.

In another version of the previous. embodiment, the amount of stretchingof the intermediate O-ring is in excess of about 15%.

The previously-described advantages and features, as well as otheradvantages and features, will become readily apparent from the detaileddescription of the preferred embodiments that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a top plan view of one embodiment of the plug-style airconditioning service valve of this invention;

FIG. 1B is a longitudinal sectional view, taken along line 1B-1B of FIG.1A, showing the main components thereof;

FIG. 1C is a perspective view, in longitudinal section, similar to thatof FIG. 1B, with a like showing;

FIG. 2A is a top plan view of the valve body, in an unassembledcondition, of the valve of this invention;

FIG. 2B is a longitudinal sectional view, taken along line 2B-2B of FIG.2A;

FIG. 2C is an enlargement of circled area C of FIG. 2B;

FIG. 2D is an end view, looking in the direction of line 2D-2D, adjacentto FIG. 2A;

FIG. 3 is a top plan view, with the seals shown in section, of a firstembodiment of a valve stem of the present invention showing same in afirst position;

FIG. 3A is a lateral sectional view, taken along line 3A-3A of FIG. 3;

FIG. 3B is a longitudinal sectional view, taken along line 3B-3B of FIG.3;

FIG. 3C is a further top view of the first embodiment of a valve stem ofthe present invention showing same in a second position, rotationallydisplaced from the position of FIG. 3;

FIG. 3D is an end view, looking in the direction of line 3D-3D, adjacentto FIG. 3;

FIG. 4A is a top plan view of the valve retainer member of the presentinvention;

FIG. 4B is an end view of the retainer member of FIG. 4A;

FIG. 5A is a top plan view of a first embodiment of a valve sealing capof the present invention;

FIG. 5B is a longitudinal sectional view, taken along line 5B-5B of FIG.5A, showing the interior structure thereof;

FIG. 5C is a top plan view of a second embodiment of a valve sealing capof the present invention;

FIG. 5D is a longitudinal sectional view, taken along line 5D-5D of FIG.5C, showing the interior thereof;

FIG. 5E is an enlargement of circled area E of FIG. 5D;

FIG. 6A is a longitudinal view, partly in section, of the valve of thepresent invention, showing same in an open position;

FIG. 6B is a view, similar to that of FIG. 6A, but showing the valve ina closed position;

FIG. 7 is a free body diagram illustrating the effect of frictionalforces acting on an O-ring seal used in the present invention;

FIG. 8 is an exploded top plan view of another embodiment, including atwo-part valve stem, of the present invention;

FIG. 8A is a longitudinal sectional view, taken along line 8A-8A of FIG.8, showing one part of this two-part valve stem;

FIG. 8C is an enlargement of the second sealing groove, in its installedposition, in FIG. 8E;

FIG. 8D is an exploded perspective view, similar to that of FIG. 8 butangularly rotated relative thereto; and

FIG. 8E is a perspective view, similar to that of FIG. 8D, but showingthe completed assembly of this two-part valve stem.

DETAILED DESCRIPTION OF THE INVENTION

While only two main embodiments of this invention will be described, theinvention should not be construed as being limited to the particularforms described herein which are to be regarded as illustrative ratherthan restrictive. Therefore, variations and changes may be made by thoseskilled in the art without departing from either the scope or spirit ofthe invention.

Turning now to the several drawings, illustrated in FIGS. 1A, 1B and 1Care the main components of a first embodiment 20 of the Plug-style AirConditioning Service Valve (hereinafter “valve”) of the presentinvention, namely: valve body 22, stem 24, retainer 26 and cap 28. FIGS.2A, 2B, 2C and 2D illustrate valve body 22 in detail, with body 22preferably being constructed of a metallic alloy and having ahexagonally-shaped outer surface 30. Valve body 22 includes alongitudinal, central, generally cylindrical chamber, cavity or bore 32,having a cylindrical inner surface 34 and a predetermined inner diameter36, into which stem 24 is inserted or assembled, as best seen in FIGS.1B and 1C. Valve body 22 further includes lateral, coaxial inlet andoutlet openings 40, 42, respectively, which together define a valve bodylateral through bore 44, with openings 40, 42 being chamfered orrelieved to break their inner sharp edges 46, at chamber cylindricalsurface 34, in order to protect a seal 98 (FIG. 3C) to be discusses indetail later. Valve body 22, at openings 40,42 also includes opposedbraze pockets 50, into which the ends of tubing portions, such as thoseshown as 52 in FIG. 3C, can be brazed. A pair of mounting holes 48 islocated near the closed end of valve body 22.

Valve body 22 additionally includes, near the open end of chamber 32, anexteriorly threaded portion 58 and an integral or contiguouslongitudinally extending, cylindrical pocket portion or recess 60 havingan internal diameter 62 slightly greater in diameter than chamberdiameter 36, thus intersecting at a shoulder 64, and an exteriordiameter 66 smaller than that of threaded portion 58. Pocket portion 60also. includes an outer peripheral surface 68 and a nose or collarportion 70. As will be explained in more detail later, retainer 26 isadapted to be placed into pocket portion 60, as best seen in FIGS. 1Band 1C, and is bounded therein by shoulder 64. Pocket portion 60, byreason of its reduced wall thickness, relative to threaded portion 58,permits the subsequent swaging of at least nose or collar portion 70over one edge surface of retainer 26 to withstand the internal pressureof valve 20 while keeping stem 24 axially fixed as well as keepingretainer 24 from rotating.

Continuing now with FIGS. 3, 3A, 3B, 3C and 3D, illustrated therein isstem 24, preferably also constructed of a metallic alloy, comprised of,on one end, of a generally cylindrical plug or plug portion 74, having aperipheral surface 76 and a predetermined diameter 78 adapted for aclose tolerance fit relative to. valve body chamber 32, as best seen inFIGS. 1B and 1C. Integral or contiguous with plug 74 and extending fromone end thereof is an actuating portion 80. Plug 74 includes a first orprimary, through, lateral passageway 84 of a. diameter substantiallysimilar to that of valve body through hole 44, with passageway 84, whenplug 74 is fully seated in valve body chamber 32, in an open position ofvalve 20, being coaxial with through hole 44 as defined by inlet andoutlet openings 40, 42 respectively, as best illustrated in FIGS. 1B and1C, thereby providing a first flow path for fluid through valve 20.

Plug 74 further includes a second or auxiliary, smaller diameter,lateral passageway 86, normal to, emanating from and communicating firstlateral passageway 84 with valve body chamber 32 at plug peripheralsurface 76 a that is 90 degrees angularly disposed or removed from plugfirst passageway 84. In addition, plug 74 also includes an end or first,conventional, circular, peripheral seal or O-ring receiving groove 88,extending circumferentially of plug portion 74 at the outer end thereof,adjacent to stem actuating portion 80. First groove 88 serves to retainand contain an elastomeric end or first seal or O-ring 90 that functionsto seal stem 24 relative to valve body central chamber peripheralsurface 34,

Furthermore, plug 74 includes an intermediate or second seal groove 92having a serpentine, undulating or labyrinth shape, with second groove92 including first and second contiguous groove portions 94 and 96,respectively. Specifically, second seal first groove portion 94 isdisposed above plug first lateral passageway 84 and thus, upon theinstallation of stem 24 in valve body 22, above valve body openings 44,42 that define valve body lateral through bore 44. Second seal firstgroove portion 94 extends substantially semi-circumferentially of plug74 and is parallel with adjacent first seal groove 88 as well as beingaxially located intermediate passageway 84 and first seal groove 88. Theessentially diametrically opposed ends of second groove first portions94 merge smoothly into second groove second portions 96 which extendsdownwardly below inlet/outlet portions 40/42 in an undulating manner asbest seen in FIGS. 3 and 3C and is generally U-shaped when viewed in itsangular extent. It should be understood that second undulating sealsecond receiving groove portion 96 is located and received in plugperipheral surface 76 b, diametrically opposite from plug peripheralsurface portion 76 a, as well as being 90 degrees angularly removed ordisplaced from first lateral passageway 84. Describing same slightlydifferently, second seal second receiving groove portion 96 extends fromone end of second seal first receiving groove portion 94 downwardly tobelow inlet/outlet openings 40/42 and then curves back upwardly, inmirror-image fashion, to seamlessly connect with the other end of sealgroove portion 42.

An elastic or elastomeric intermediate or second seal or O-ring 98 of,for example a neoprene composition, as well as standard circular crosssection and standard annular shape, upon its installation in second sealgroove 92, assumes the previously-described shape thereof. Second sealor O-ring 98 is spaced apart from first seal or O-ring 90, thus definingtherebetween, via plug peripheral surface 76 b and valve bodycylindrical surface 34, a closed volume 106 (not shown per se) withoutlateral passageway 84. Second seal or O-ring 98 therefore includes afirst portion 100 contiguous with a second undulating portion 102, thelatter being received in undulating second seal groove second portion96, with portion 102, together with seal groove second portion 96,extending below inlet/outlet openings 40/42 such that one ofinlet/outlet openings 40/42 is disposed outside of closed volume 104when plug 74 is in a closed position, i.e., when plug surface portion 76b is aligned. with inlet opening 40 and plug surface portion 76 a,including plug second lateral passageway 86, is aligned with outletopening 42.

One of the obstacles, prior to this invention that kept plug valves frombeing utilized in air conditioning service-type valve applications isthat there are no commercially available O-ring compositions that arefully compatible with the R-22 refrigerant and mineral oil combinationcurrently in use. Specifically, the obstacle resides in the swelling ofthe O-rings, in refrigerant applications, due to the absorption of therefrigerant medium. This obstacle is removed in this invention via theuse of serpentine, labyrinth or undulating seal seat groove 92, asdescribed, whose shape or geometries permit the initial orpre-stretching of O-ring 98 preferably in excess of about 15%, but notlimited thereto, during the installation thereof, in order to offset orcounteract the noted refrigerant absorption effects. If not initiallystretched within the noted range, the O-ring circumferential extent,during use, becomes too large and the O-ring will become loose withinits retaining groove. In addition, a second deleterious effect of thenoted swelling is that it also causes the O-ring diameter to increase,thus increasing its cross sectional size, resulting in an undesirablefrictional increase during stem rotation. Thus, it is preferable to useserpentine retaining groove 92 since it extends 360 degrees, in aconvoluted manner, around the periphery of cylindrical plug 74. In theprior art designs, such as in previously noted U.S. Pat. Nos. 4,262,880and 5,234,193, the inlet O-rings are housed or retained in only onecurved side surface portion of their cylindrical stems, namely aroundtheir inlet passages or orifices. In this type of construction, thereare no radially inwardly directed forces acting on these O-rings to keepsame in their grooves, but rather only forces parallel or tangential tothe longitudinal axes of the seals. In contrast thereto, as bestdiagrammatically illustrated in FIG. 7, in the present invention, whenvalve stem 24 is turned, particularly when it rotates past housing inlethole 40, frictional turning forces (F-TURNING, in FIG. 7) from valvebody 22 will act upon O-ring 98 but since its labyrinth designcompletely surrounds stem 24 in a specific undulating manner, thefrictional forces act on O-ring 98 laterally and/or tangentially, withthe radial components thereof being countered or opposed by the noted,inwardly-directed forces (F-STRETCH, in FIG. 7) on O-ring 98 resultingfrom the initial stretching thereof. In the previously-noted prior artconstructions, when the O-ring is located only on the side of the stemand is stretched, the resulting forces do not act toward thelongitudinal axis of the stem but will rather be parallel to thelongitudinal axis thereof so that, when the frictional forces resultingfrom the turning of the stem act on the O-ring, they will be acting inthe same direction as the stretch forces that complement or augment thefrictional forces that cause the leading edge of the O-ring to move outof its retaining grove.

Continuing with the description of stem 24, actuating portion 80 thereofemanates from plug 74 at the latter's axial outer end surface 108 andincludes a generally cylindrical central stem portion 110, of apredetermined axial extent, of reduced diameter, relative to plug 74,including a radially-extending stop member or pointer 112, bestillustrated ion FIG. 3D. Adjoining cylindrical stem portion 110 is atool receiving portion 114, preferably of hexagonal shape in crosssection and adapted to permit a 90 degree rotation of stem 24 from opento closed position, and vice versa, of valve 20. Axially extending fromthe outer end surface of tool receiving portion 114 is a small diametercentral service fitting 116 which includes an exteriorly threadedattachment portion 118 onto which a service hose fitting (not shown) canbe threaded. Stem 24 also includes a central axial service passageway120 that extends from plug lateral first through passage 84 fullythrough stem actuating portion 80 and which terminates into servicefitting 116. Preferably, a valve core, of any desired known constructionis fixedly retained within the axial outer end of service fitting 118,within axial service passageway 120.

Turning now to FIGS. 8 and 8A-8E, illustrated therein is a secondembodiment 20′ which includes a second embodiment of stem 24′. Sincestem 24′ has many structural portions and features in common with stem24, like numerals are used for like parts, with the addition of a prime(′) suffix. Stem 24′ differs from stem 24 mainly in that plug 74′ ofstem 24′ is comprised of an upper or female member 166 and a cooperatinglower or male member 168 as best seen in FIGS. 8 and 8D. Male member 168includes an internal, central, axial boss portion 170 having an axialkey portion 172, best seen in FIG. 8D. Male boss portion 170, which isaxially directed toward female member 166, is adapted to beinterference-fitted, such as via a press fit, into a facing internal,central, axial, blind aperture 176 in female member 166, best seen inFIG. 8A. A key recess portion 178, in aperture 176, functions to receivemale key portion 172, with key and key-receiving portions 172, 178respectively, cooperating to inhibit any angular rotation betweenmembers 166 and 168. Completed stem assembly 24′ is illustrated in FIG.8E.

Plug 74′ includes a first or end seal groove 88′ that houses first orend seal or O-ring 90′ (shown in FIGS. 6A, 6B) in the manner alreadypreviously-described. Plug 74′, comprised of cooperating female member166 and male member 168, as best shown in FIG. 8E, also includes asecond or intermediate, undulating, labyrinth or serpentine seal orO-ring groove 192 that, while being similar to groove 92, differstherefrom in that its bottom surface 194 and adjoining, integral, sidewall 196 are formed in female member 166 while its separate, opposite,side wall 198 is formed in male member 168, all in a manner known in theart. Thus, groove 192 is not formed until members 166 and 168 are fittedtogether, with FIG. 8C being an enlarged sectional view of secondsealing groove 192, in its installed position, in FIG. 8E. In addition,each one of side walls 196, 198 includes an inwardly tapering orinclined lip portion 200 whose convergences aid in the retention ofsecond or intermediate seal or O-ring 98′ (shown in FIGS. 6A, 6B) in themanner already previously described. The remaining structures andfunctions of stem 24, such its the various passages and actuatingportion 80′, etc. are substantially similar to those already previouslydescribed, relative to stem 24, and will not be further described forthe sake of brevity.

FIGS. 4A and 4B illustrate generally annular retainer member 26 which isadapted to be positioned around cylindrical actuating stem portion 110as best illustrated in FIGS. 1B and 1C. Retainer 26, preferablyconstructed of a. metallic alloy, is generally annular in shape, withits inner axial end surface 126 abutting plug axial outer end surface108 upon its insertion around stem portion 110 and with its axial outersurface 128 preferably being provide with an instruction logo, such as“open” and an arrow for indicating the direction of rotation for “open”.The outer peripheral surface 130 is provided with an undulating textureor pattern, such as repeated grooving 132. The inside diameter 134 ofretainer 26 is smaller than diameter 78 of plug 74 so that, onceretainer 26 is secured to valve body 22, stem 24 cannot be axiallyremoved from valve body 22 when the latter contains a pressurizedmedium. Retainer 26 is preferably slip-fitted within housing pocketportion 60. Pattern 132 aids in the slip fitting process and upon thecompletion thereof, valve body nose or collar portion 70 is inwardlyswaged over the intersection of pattern 132 and retainer outer endsurface 128. This effectively not only axially restrains plug 74 butalso inhibits the rotation of retainer 26. Retainer member innerdiameter 134 is provided with a recessed angular portion 136 forreceiving stem portion stop member or pointer 112, with recessed portion136 having opposed end stop surfaces 138, 140 that limit the angularrotational movement of stop member 112 and consequently that of stem 24to about 90 degrees.

Advancing now to FIGS. 5A and 5B, illustrated therein is a firstembodiment of a cap 28 for sealing valve central chamber or cavity 74and protecting the part of actuating portion 80 of stem 24 protrudingtherefrom. Cap 28, which may be of metallic or plastic construction,depending on the expected operational environment, includes a base 144having an interiorly-threaded portion 146 as well as a textured orpatterned annular exterior surface 148, such as repeated grooving, forexample, for enhancing its operator-gripping properties. Base portion144 merges smoothly into an integral or contiguous, generally truncatedcone portion 150 which, together with the interior volume of baseportion 144, forms an internal cavity 152. Cap threaded portion 146 isadapted to operatively mate with valve body exteriorly threaded portion58. In addition, the inner surface of base portion 144 is provided withan interference diameter portion 156 and a smaller diameter gland orrecess 158 that serves to house an elastomeric third or cap seal orO-ring member 160 which, in turn, is adapted for sealing against thecurved outer surface 72 (after swaging) of housing pocket portion 60.The nose or collar 70 of housing 22, together with cap interferencediameter portion 156, can for example, be designed and producedaccording to the teachings of U.S. Pat. No. 6,546,952B1, to Martin etal., which is also assigned to the assignee of the present invention.The Martin et al., construction requires that nose or collar 70 beswaged over retainer 26 before cap 28 can be attached to valve body 22,otherwise cap 28 does not fit on valve body 22 which in turn signifiesthat stem 24 is not retained within valve body cavity 32. As a result,the manufacturer is provided with simple verification that stem 24, infact, is not structurally retained within valve body 22.

Proceeding now to FIGS. 5C, 5D and 5E, illustrated therein is a secondembodiment of protective or sealing cap 28′ which can also be acomponent of second embodiment 20′ of the Plug-Style Air-ConditioningService Valve of the present invention. Since cap 28′ is similar to cap28, like numerals are used for like parts, with the addition of a prime(′) suffix. Cap 28′ differs from cap 28 in that generally-truncated coneportion 150′ of the former includes a plurality ofcircumferentially-spaced, longitudinally extending, reinforcing ribportions 151 which also enhance its operator gripping properties. Inaddition, portion 150′ is provided with a generally circular outer endsurface 153 having a tool-receiving recess 154, such as of hexagonalperipheral geometry to accept a wrench, for example. Recess 154 is ofadvantage when space is very tight and direct hand access may bedifficult.

Furthermore, at least one of the inner and outer peripheral wallsurfaces 159 a, 159 b of gland or cap inner recess portion 158′ isprovided with a peripheral thread portion 162, shown in detail in FIG.5E. Thread portion 162 functions not only to retain O-ring seal 160′within recess portion 158′ due to its inherent helical angulation, butalso has the added advantage of allowing gradual pressure equalizationbetween cavity 152′ and the outside atmosphere with even only a partialturn or rotation of cap 28′.

In terms of the operation of valve 20, stem actuating portion axialservice passageway 120 and second or auxiliary lateral passageway 86have their inner ends merging into first or primary lateral passageway84 to allow service fitting 118 to “communicate” with the airconditioning system fluid when valve 20 is in the closed position, whichis illustrated in FIG. 6B. As previously noted, stem 24 locatestraditional first seal or O-ring 90. When the air conditioningcondensing unit is pre-charged, valve 20 is in the closed position, andin this closed position, serpentine second seal or O-ring 98 ispositioned in-line with valve body lateral through hole 44 which, inturn, is attached, via one of tubings 52, to the condensing unit. Thistraps the refrigerant medium between traditional O-ring 90 andserpentine or undulating O-ring 98. It is important to understand that,upon the opening of valve 20, the refrigerant medium is trapped belowundulating O-ring 98, as illustrated in FIG. 6A, thus allowingtraditional O-ring 90 to act as a redundant or secondary seal. As noted,stem 24 includes tool receiving portion 114, for tool location, topermit 90 degree rotation of stem 24 from the open to the closedposition and vice versa. Furthermore, stop member 112, which also servesas a pointer, is positioned within retainer recessed portion 136. Inaddition, retainer 26 is positioned within valve body 22 in a manner soas to allow valve 20 to be in the open position when pointer 112 iscontacting open-stop surface 138. Similarly, valve 20 is in the closedposition when pointer 112 is contacting closed-stop surface 140.

It is deemed that one of ordinary. skill in the art will readilyrecognize that the several embodiments of the present invention fill aremaining need in this art and will be able to affect various changes,substitutions of equivalents and various other aspects of the presentinvention as described herein. Thus, it is intended that the protectiongranted hereon be limited only by the scope of the appended claims andtheir equivalents.

1. An air conditioning service plug-type valve, comprising incombination: a. a valve body having a chamber and. an inlet opening andan outlet opening communicating with said chamber, said valve bodyincluding, at an open end of said chamber, an exteriorly threadedportion and a generally cylindrical pocket portion having a deformablecollar; b. a stem, including a generally cylindrical plug with aperipheral surface, located on one end and a contiguous actuatingportion extending from another end thereof, said plug being disposedwithin said chamber and being rotatable within said chamber, about anaxis between a closed position and an open position; c. said plugincluding a first, through, lateral passageway communicating with saidinlet and outlet openings when said plug is in said open position,thereby providing a first flowpath for the fluid through said valve,said inlet and outlet openings, together with said first lateralpassageway, being disposed along a straight axis when said plug is insaid open position; d. said plug further including a second lateralpassageway normal to, emanating from and communicating said firstlateral passageway with said valve body chamber; e. a first seal,disposed between said valve body and said plug in a first seal groove insaid plug peripheral surface; f. a second seal, disposed between saidvalve body and said plug in a second seal groove, of a serpentine shapeand including contiguous first and second seal groove portions, in saidplug peripheral surface, said second seal being stretched apredetermined amount during its installation into said second sealgroove and being spaced apart from said first seal and defining,therebetween and said valve body and said plug, a closed volume withoutsaid first lateral passageway; g. said second seal, upon installationthereof in said second seal groove assumes the shape of said second sealgroove, thus including first and second contiguous seal portions, saidfirst seal portion being disposed above said inlet and outlet openings,said second seal portion extending from one end of said first contiguousseal portion downwardly to below said inlet and outlet openings and thenback upwardly to another contiguous end of said first seal portion suchthat one of said inlet. and outlet openings is disposed within saidclosed volume and the other of said inlet and outlet openings isdisposed outside of said closed volume when said plug is in said closedposition; h. said stem contiguous actuating portion including agenerally cylindrical portion, including a radially extending stopmember, adjoining said plug, a tool-receiving portion adjoining saidgenerally cylindrical stem portion, and a service fitting adjoining saidtool-receiving portion, said stem further including a central axialpassageway normal to, emanating from and communicating said firstlateral passageway with said service fitting, said service fitting beingadapted for receiving a valve core for refrigerant medium chargingpurposes; i. a generally annular retainer member positioned around saidstem cylindrical portion, axially within said valve body pocket portion,with the inside diameter of said retainer member being smaller than thediameter of said plug and having a recessed portion of a predeterminedcircumferential extent, with said stop member being received within saidrecessed portion, said valve body deformable collar being adapted to beradially inwardly swaged over said retainer member during the assemblyof said valve; j. a cap for sealing said valve cavity and protectingsaid stem actuating portion, said cap including an interiorly threadedbase portion, adapted to mate with said threaded valve body portion, andan integral truncated closure portion having an internal cavity forcovering said service fitting and valve core; and k. a third seal,located in an internal gland portion of said cap, adapted for sealingsaid cap against said valve body swaged collar portion, upon assembly ofsaid cap onto said valve body.
 2. The air conditioning service plug-typevalve of claim 1, wherein said second lateral passageway is angularlyspaced about 90 degrees from said first lateral passageway.
 3. The airconditioning service plug-type valve of claim 1, wherein said secondseal groove includes a second seal first groove portion beingsubstantially parallel with said first seal first groove, for retainingsaid second seal first portion, and a contiguous second seal secondgroove portion, said second groove portion being generally U-shaped inits angular extent, for supporting said second seal second portion. 4.The air conditioning service plug-type valve of claim 3, wherein saidsecond seal first groove portion is substantially semicircular inangular extent.
 5. The air conditioning service plug-type valve of claim3 wherein said second seal second groove portion is substantiallysemicircular in angular extent.
 6. The air conditioning serviceplug-type valve of claim 3 wherein said second seal first grooveportion, together with said second groove portion is substantiallycircular in angular extent.
 7. The air conditioning service plug-typevalve of claim 1, wherein the amount of stretching of said second sealis in excess of about 15%.
 8. In an air conditioning service plug-typevalve, a stem, comprising: a. a generally cylindrical plug with aperipheral surface, located on one end thereof and a contiguousactuating portion extending from another end thereof, said plug beingdisposed in valve body having a chamber and inlet and outlet openingscommunicating with said chamber, said plug being rotatable within saidchamber about an axis between a closed position and an open position; b.said plug including a first, lateral through passageway communicatingwith said inlet and outlet openings when said plug is in said openposition, thereby providing a first fluid path through said valve, saidinlet and outlet openings, together with said first passageway, beingdisposed along a straight axis when said plug is in said open position;c. said plug further including a second lateral passageway normal to,emanating from and communicating said first lateral passageway with saidvalve body chamber; d. a first seal groove in said plug peripheralsurface for retaining a first seal therein; e. a second seal groove insaid plug peripheral surface, of a serpentine shape, for retaining asecond seal therein, said second seal being stretched a predeterminedamount during its installation into said second seal groove and beingspaced apart from said first seal groove and defining, therebetween andsaid valve body and said plug, a closed volume without said firstlateral passageway; and f. said contiguous actuating portion including agenerally cylindrical portion including a radially extending stopmember, adjoining. said plug, a tool-receiving portion adjoining saidgenerally cylindrical portion, and a service fitting adjoining saidtool-receiving portion, said stem further including a central axialpassageway normal to, emanating from and communicating said firstlateral passageway with said service fitting, said service fitting beingadapted for receiving a valve core for refrigerant medium chargingpurposes.
 9. The stem of claim 8, wherein second seal groove includes asecond seal first groove portion, substantially parallel with said firstseal groove, for retaining said second seal first portion, and acontiguous second seal second groove portion, substantially U-shaped,for retaining said second seal second portion.
 10. The stem of claim 8wherein at least one of said second seal first and second grooveportions is substantially semicircular in angular extent.
 11. The stemof claim 8, wherein the amount of stretching of said second seal is inexcess of about 15%.
 12. The stem of claim 8, wherein said secondlateral passageway is angularly spaced about 90 degrees from said firstlateral passageway.
 13. A plug-type valve comprising in combination: a.a valve body having a central chamber and angularly spaced inlet andoutlet openings communicating with said chamber, said valve bodyincluding, at an open end of said chamber, a threaded portion and agenerally cylindrical pocket portion having a deformable collar; b. astem, including a cylindrical plug with a peripheral surface, located atend and an integral actuating portion extending from another endthereof, said plug being disposed within said chamber and beingrotatable about an axis between closed and open positions; c. said plugincluding a primary lateral through passage communicating with saidinlet and outlet openings when said plug is in said open position,thereby providing a first flowpath through said valve, said inlet andoutlet openings, together with said primary passage, being coaxial whensaid plug is in said open position; d. said plug further including anauxiliary lateral passage normal to, emanating from and communicatingsaid primary passage with said valve body chamber, said auxiliarypassage being angularly disposed about 90 degrees from said primary.lateral passage; e. an end O-ring, disposed between said valve body andsaid plug in an end seal groove in said plug peripheral surface; f. anintermediate O-ring, disposed in said plug peripheral surface betweensaid valve body. and said plug in an intermediate O-ring groove of aserpentine shape and having integral first and second O-ring portions,said intermediate O-ring being stretched a predetermined amount duringits installation into said intermediate O-ring groove and defining,therebetween and said valve body and said plug, a closed volume withoutsaid primary passage; g. said intermediate O-ring, upon saidinstallation, assuming the serpentine shape of said intermediate O-ringgroove, thus including first and second integral O-ring portions, saidfirst O-ring portion being disposed on one side of said inlet and outletopenings, said second O-ring portion extending therefrom to another sideof said inlet and outlet openings and then back to another end of saidfirst O-ring portion such that one of the inlet and outlet openings isdisposed within said closed volume and the other of said inlet andoutlet openings is disposed outside of said closed volume when said plugis in said closed position; h. said stem actuating portion including acylindrical stem portion, having a stop member, adjoining said plug, atool-receiving portion adjoining said stem portion, and a servicefitting adjoining said tool receiving portion, said stem furtherincluding a central axial passage normal to, emanating from andcommunicating said primary lateral passage with said service fitting,the latter including a valve core for gaseous medium charging purposes;i. an annular retainer member positioned around said cylindrical stemportion, axially within said valve body pocket portion, with the insidediameter of said retainer member being of a diameter smaller than thatof said plug and including a recessed portion, with said stop memberbeing received therein, said valve body deformable collar being inwardlydeformed over said retainer member; j. a cap, for sealing said valvecavity and said stem actuating portion, having a threaded base portion,for mating with said valve body threaded portion, and an integralclosure portion having an internal cavity for covering said servicefitting; and k. a cap seal, located within said cap, for sealing saidvalve body deformed collar portion.
 14. The plug-type valve of claim 13,wherein said intermediate O-ring groove includes a first groove portion,substantially parallel with said end O-ring groove, for retaining saidintermediate O-ring first portion, and an integral intermediate O-ringsecond groove portion, of general U-shape in its angular extent, forretaining said intermediate O-ring second portion.
 15. The plug-typevalve of claim 13, wherein the angular extent of at least one of saidintermediate O-ring first and second portions is about 180 degrees. 16.The plug-style valve of claim 13, wherein the amount of stretching ofsaid intermediate O-ring is in excess of about 15%.